21501023134240 has 288 divisors, whose sum is σ = 58259029006080. Its totient is φ = 7469365542912.

The previous prime is 21501023134229. The next prime is 21501023134247. The reversal of 21501023134240 is 4243132010512.

It is a junction number, because it is equal to n+sod(n) for n = 21501023134199 and 21501023134208.

It is not an unprimeable number, because it can be changed into a prime (21501023134247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1875028987 + ... + 1875040453.

It is an arithmetic number, because the mean of its divisors is an integer number (202288295160).

Almost surely, 2^{21501023134240} is an apocalyptic number.

21501023134240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21501023134240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29129514503040).

21501023134240 is an abundant number, since it is smaller than the sum of its proper divisors (36758005871840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21501023134240 is a wasteful number, since it uses less digits than its factorization.

21501023134240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15604 (or 15583 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

Adding to 21501023134240 its reverse (4243132010512), we get a palindrome (25744155144752).

The spelling of 21501023134240 in words is "twenty-one trillion, five hundred one billion, twenty-three million, one hundred thirty-four thousand, two hundred forty".